The US Navy has used dolphins to help locate — and in some cases destroy — sea mines for nearly 50 years. But now, due to escalating costs and a viable robotic alternative, the Sea Mammal Program is finally set to be retired.

Back in the 1960s, the Navy learned to exploit dolphins, by tapping into their innate capacity for echolocation — a built-in sonar that dolphins use to track and identify enemy sea mines. But while the dolphins are treated well, they are still thought of as a "system" not unlike any other military technology. Best estimates indicate that the US Navy has trained about 80 dolphins to detect mines, as well as some sea lions.

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It's important to note that the dolphins are not used to harm anyone, nor are they used to directly set off the mines (like the way the US military used herds of goats to clear minefields in Italy during World War II). Rather, after locating a sea mine, dolphins typically attach a charge or acoustic transponder and swim away.

However, this shouldn't imply that it's not perilous work. As animal rights advocate Peter Singer pointed out earlier this year, dolphins could still set off the mines and die in the resulting explosion. Moreover, by being used in this way, they immediately become targets for enemy combatants — including any other dolphins in the area.

And indeed, given that tensions are rising in the Middle East, it's suspected that Iran could start littering the Strait of Hormuz with sea mines, what is the only sea route out of the Persian Gulf — and what the US Energy Department calls "the world's most important oil choke." This would prompt the US Navy to deploy their mine sniffing dolphins in response.

But soon enough, the dolphins will be off the hook. The Navy is now set to move past the Sea Mammal Program and use robots in place of dolphins and sea lions. If all goes as planned, the program will start its phase-out process in 2017. And as Sharon Weinberger of BBC Future reports, the Pentagon will soon have the technology to do so:

In April, the Navy unveiled its plans for Knifefish, a torpedo-shaped, underwater robot that would roam the seas for up to 16 hours, looking for mines. The 7m- (20ft-) long unmanned underwater vehicle (UUV) is still in development, but should be ready by 2017, and will use sonar to hunt mines. "The Knifefish UUV is ultimately intended to be the replacement for the marine mammals," [Captain Frank] Linkous says.

And interestingly, it's not just dolphins that are being moved out of service by robots:

[T]he Navy is also hoping to at least reduce reliance on humans who perform dangerous bomb disposal missions, known as explosive ordnance disposal (EOD). The Navy has been moving quickly to rush new robotic technologies to the field, including an unmanned underwater vehicle, known as the Kingfish, and four unmanned surface vessels that the Navy originally bought for anti-submarine warfare, but are now being outfitted with sonar to hunt mines.

The Navy is also buying the German-made SeaFox mine hunting system, another robotic underwater vehicle that is guided by a fibre-optic cable and can be used to attach a charge to a mine. Right now, naval divers that are trained as explosive ordnance disposal technicians carry out many critical mine clearing tasks, but technology like the SeaFox will help reduce the number of dives these personnel have to make, according to Linkous.

"This is very much like the concept that EOD technicians have done on the ground in Afghanistan and Iraq: greater use of robotic systems to neutralise and destroy IEDs in the field," Linkous says. "It's the same concept."

Of course, lots could happen in the Middle East between now and 2017. So until that time, the dolphins will have to remain on standby.